Mechanical percussive tool



May 17, 1932. K. HAAGE ET Al. 1,858,707

MECHANICAL PERCUSSIVE TOOL Filed June 8, 1929 3 Sheets-Sheet l May 17,1932. y K. HAAGE ET Al. 1,858,707

MECHANICAL PERCUSSIVE TOOL Filed Jung e, 1929 3 sneetsLsneet 2 auf* 5 Sheets-Sheet 5 .DMS m K. HAAGE ET AL- Filed June 8,` 1929 c .lccccccc May 17, 1932.

MECHANICAL PEncussIvE Tool.

nonnina-u Konrad Haaye and Ala/t Pflger @y Patented May 17, 1932 UNITED STATES PATE-NT OFFICE MECHANICAL PERCUSSIVE TOOL Application led June 8, 1929, Serial No.

Our invention relates to mechanical percussive tools, for instance to hand rammers, as described in our copending U. S. application Serial No. 221,726, Patent No. 1,755,361, April 22, 1930. ,It is an object of our invention to so design a tool of the kind described that it is possible to provide a part of increased diameter at the end of the strike rod, in order to distribute the ramming pressure over a larger area. To this end we provide a connection between the piston and the strike rod' which permits independent movement, within limits, of the piston and the strike rod so that the widened part at the end of the` strike rod which cannot be retracted into the tup, will not interfere with the inward movement of the piston.

In the drawings affixed to this specificationl and forming part thereof rammers embodying ourv invention are illustrated diagrammat-ically by way of example, all figures being axial sections.

In the drawings Figs. 1 to 5 illustrate various positions of a rammer for light metalling, A

Fig. 6 illustrates a rammer in which the widened end of the strike rod is provided with a guard,

Figs. 7 and 8 illustrate a rammer for driving piles in the positions corresponding to Figs. 1 and4.

Referring now to the drawings, and first to Figs. 1 to 5, s is a valve for admitting combustible mixture to the cylinder a of the rammer, c isl the cylinder head with a valve casing at the top, d are handles on the cylinder head, t is a valve lever, and 7' is a handle for reciprocating the piston. These parts which are fully described in our said copending application, have been indicated in Fig. 1 only.

b is a tup at the lower end of the cylinder, e is a piston fitted to slide in the cylinder, m is a rod which, however, in contradistinction to the rammer described in our sai'dcopending application, is. not secured to the piston and therefore will be referred to as the strike rod, n .is a plate or other extension at the lower lend of the strike rod m, o is a spring plate mounted to slide on'the strike rod with its tubular hub, p is a spring interposed be- 369,285r and in Germany June 13, 1928. i

tween the plate o and the head of the piston e, Q is a spring interposed between the tup I) and the spring plate o, and u are exhausty slots in the wall of the cylinder a.

The length of the strike rod m with respect to the overall length of the cylinder and the tup is so determined that in the initial position of the rammer, as shown in Fig. 1, there is a clearance z equal to the charging stroke between the lower face of the piston head and the top of the cylinder head. When it is desired to start`the rammer thepiston e is raised as far as the lower face of the cylinder head by means of the handle 7' and is then lowered into contact with the end of the strike rod m drawing mixture into the combustion chamber through the valve s. The valve is now closed by the lever t and the mixture is ignited. The ignited and expanding mixture raises the cylinder aas shown in Fig. 2. At the end of the expanding stroke the products of combustion are discharged through the slots u, the spring p forces the piston up in the cylinder, the valve s which remains closed during the expansion stroke,

is opened by its spring and part of the exhaust is 'discharged through the valve. By 4the momentum imparted to the cylinder, the tup and the cylinder head, the rammer is raised from the ground as shown in Fig. 3, while the spring g is compressed between the plate o and the tup The reactions of the spring p and the spring g which is expanding after having been compressed, move the piston e further u in the cylinder. The piston closes the ex laust ports u and linally strikes the cylinder head as shown in Fig. 4. The spring g now expands and moves up the spring plate o the tubular hub of which entrains the rod m by frictiontion of the spring plate 0 is determined by the resultant force exerted thereon by the springs g and p but the rod m is free to move on by inertia, until the plate n is arrested by the lower face of the tup. The rammer after reaching its highest position, falls down onto the ground as shown in Fig. 5. The piston e continues its downward movement by inertia, drawing fresh mixture into the cylinder, and finally is arrested by the strike The inal posirod m as shown in Fig. 1. The rammer is now ready for another cycle. The spring plate o may be dispensed with and the spring p may be abutted on the upper face of the tup b, like the sprino g, but the length of the rspring g should be so determined that it will only engage below the piston head after spring p has been compressed to a corresponding extent.

If the rammer is to be used for ramming concrete or the like or if for any other reason it is necessary to avoid access of foreign matter to the strike rod m and its guides a guard lv is placed on the plate n as shown in Fig. 6.

When driving piles as illustrated in Figs. 7 and 8, the strike rod is not raised from the pavement or the like but the strike rod m is permanently inserted in the pile. To this end it is provided with a small flange as instead of the plate n and inserted in a bore of the pile fw with an extension beyond the flange The rod remains in the pile until the pile has been driven. As the rod mis not raised with the rammer, the spring g and the' seat o are eliminatedyonly the spring p' being inserted between the tup and the piston. Otherwise the operation is thesame as described with reference to Figs. l to 5, Fig. 7 showing the initial position corresponding to Fig. l, and Fig. 8 showing the iinal position corresponding to Fig. 5.

y It will appear that by separating the piston and the strike rod instead of positively connecting them as described in our copending application, it is possible to provide a plate m, a ange ai, or any other projection, at the lower end of the strike rod as it is not necessary that the rod should recede into the tup as in the case of our copending. ap-

plication. By providing the plate n the area which is acted on by the hammer may be increased beyond that o the tup as shown in Fig. 6 and in connection with the driving of piles, it' is possible to secure the rod permanently on the pile through the medium of the flange until the pile has been driven.

We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

In the claims aiixed to this. specification no selection of any particular modification of the invention is intended to the exclusion of other modifications thereof and the right to subsequently make claim to any modification not covered by these claims is expressly reserved.

We claim l. A mechanical percussive tool comprising a rod, a cylinder having a tup at its lower end which is fitted to slide on said rod, and' a piston mounted to slide in said cylinder so as to form a combustion chamber with the top of said cylinder and adapted to move independently of, and to come into engagement with, said rod.

2. A mechanical percussive tool comprising a rod, a cylinder having a tup at its lower end which is tted to slide on said rod, and a piston mounted to slide in said cylinder so as to form a combustion chamber with the top of said cylinder and adapted to move independently of, and to come into engagement with, said rod, the length of said rod being so determined,` with respect to the length of said cylinder that a clearance equal to the suction stroke of said piston is left between said piston and the upper end of the cylinder in the'upper final position of said rod with respect to said cylinder.

In testimony whereof we aflix our signatures.

KONRAD HAAGE. ALBERT PFLGER. 

